Auto-set GUI for custom layer order when API call to QgsProject::setLayerOrder

is made

src/gui/layertree/qgslayertreemapcanvasbridge.cpp

@@ -37,6 +37,7 @@ QgsLayerTreeMapCanvasBridge::QgsLayerTreeMapCanvasBridge( QgsLayerTreeGroup *roo
   connect( root, &QgsLayerTreeGroup::customPropertyChanged, this, &QgsLayerTreeMapCanvasBridge::nodeCustomPropertyChanged );
   connect( root, &QgsLayerTreeGroup::removedChildren, this, &QgsLayerTreeMapCanvasBridge::nodeRemovedChildren );
   connect( root, &QgsLayerTreeNode::visibilityChanged, this, &QgsLayerTreeMapCanvasBridge::nodeVisibilityChanged );
+  connect( QgsProject::instance(), &QgsProject::layerOrderChanged, this, &QgsLayerTreeMapCanvasBridge::projectLayerOrderChanged );
 
   setCanvasLayers();
 }
@@ -141,7 +142,9 @@ void QgsLayerTreeMapCanvasBridge::setCanvasLayers()
   int currentLayerCount = layerNodes.count();
   bool firstLayers = mAutoSetupOnFirstLayer && mLastLayerCount == 0 && currentLayerCount != 0;
 
+  mUpdatingProjectLayerOrder = true;
   QgsProject::instance()->setLayerOrder( allLayerOrder );
+  mUpdatingProjectLayerOrder = false;
   mCanvas->setLayers( canvasLayers );
   if ( mOverviewCanvas )
     mOverviewCanvas->setLayers( overviewLayers );
@@ -318,3 +321,18 @@ void QgsLayerTreeMapCanvasBridge::nodeCustomPropertyChanged( QgsLayerTreeNode *n
     deferredSetCanvasLayers();
 }
 
+void QgsLayerTreeMapCanvasBridge::projectLayerOrderChanged()
+{
+  if ( mUpdatingProjectLayerOrder )
+    return;
+
+  setHasCustomLayerOrder( true );
+  QStringList ids;
+  Q_FOREACH( QgsMapLayer* layer, QgsProject::instance()->layerOrder() )
+  {
+    if ( layer )
+      ids << layer->id();
+  }
+  setCustomLayerOrder( ids );
+}
+

src/gui/layertree/qgslayertreemapcanvasbridge.h

@@ -110,6 +110,10 @@ class GUI_EXPORT QgsLayerTreeMapCanvasBridge : public QObject
     void nodeVisibilityChanged();
     void nodeCustomPropertyChanged( QgsLayerTreeNode *node, const QString &key );
 
+  private slots:
+
+    void projectLayerOrderChanged();
+
   protected:
     QgsLayerTreeGroup *mRoot = nullptr;
     QgsMapCanvas *mCanvas = nullptr;
@@ -124,6 +128,8 @@ class GUI_EXPORT QgsLayerTreeMapCanvasBridge : public QObject
 
     bool mHasFirstLayer;
     bool mLastLayerCount;
+    bool mUpdatingProjectLayerOrder = false;
+
     QgsCoordinateReferenceSystem mFirstCRS;
 };
 

tests/src/python/CMakeLists.txt

@@ -63,6 +63,7 @@ ADD_PYTHON_TEST(PyQgsGeometryValidator test_qgsgeometryvalidator.py)
 ADD_PYTHON_TEST(PyQgsGraduatedSymbolRenderer test_qgsgraduatedsymbolrenderer.py)
 ADD_PYTHON_TEST(PyQgsInterval test_qgsinterval.py)
 ADD_PYTHON_TEST(PyQgsJSONUtils test_qgsjsonutils.py)
+ADD_PYTHON_TEST(PyQgsLayerTreeMapCanvasBridge test_qgslayertreemapcanvasbridge.py)
 ADD_PYTHON_TEST(PyQgsLineSymbolLayers test_qgslinesymbollayers.py)
 ADD_PYTHON_TEST(PyQgsMapCanvas test_qgsmapcanvas.py)
 ADD_PYTHON_TEST(PyQgsMapCanvasAnnotationItem test_qgsmapcanvasannotationitem.py)

tests/src/python/test_qgslayertreemapcanvasbridge.py

@@ -0,0 +1,90 @@
+# -*- coding: utf-8 -*-
+"""QGIS Unit tests for QgsLayerTreeMapCanvasBridge.
+
+.. note:: This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+"""
+__author__ = 'Nyall Dawson'
+__date__ = '8/03/2017'
+__copyright__ = 'Copyright 2017, The QGIS Project'
+# This will get replaced with a git SHA1 when you do a git archive
+__revision__ = '$Format:%H$'
+
+import os
+
+import qgis  # NOQA
+
+from qgis.core import (QgsProject,
+                       QgsApplication,
+                       QgsUnitTypes,
+                       QgsCoordinateReferenceSystem,
+                       QgsVectorLayer)
+from qgis.gui import (QgsLayerTreeMapCanvasBridge,
+                      QgsMapCanvas,
+                      QgsCustomLayerOrderWidget)
+from qgis.testing import start_app, unittest
+from utilities import (unitTestDataPath)
+
+app = start_app()
+TEST_DATA_DIR = unitTestDataPath()
+
+
+class TestQgsLayerTreeMapCanvasBridge(unittest.TestCase):
+
+    def __init__(self, methodName):
+        """Run once on class initialization."""
+        unittest.TestCase.__init__(self, methodName)
+
+    def testCustomLayerOrderUpdatedFromProject(self):
+        """ test that setting project layer order is reflected in custom layer order panel """
+
+        prj = QgsProject.instance()
+        layer = QgsVectorLayer("Point?field=fldtxt:string",
+                               "layer1", "memory")
+        layer2 = QgsVectorLayer("Point?field=fldtxt:string",
+                                "layer2", "memory")
+        layer3 = QgsVectorLayer("Point?field=fldtxt:string",
+                                "layer3", "memory")
+        prj.addMapLayers([layer, layer2, layer3])
+
+        canvas = QgsMapCanvas()
+        bridge = QgsLayerTreeMapCanvasBridge(prj.layerTreeRoot(), canvas)
+        custom_order_widget = QgsCustomLayerOrderWidget(bridge)
+
+        #custom layer order
+        bridge.setHasCustomLayerOrder(True)
+        bridge.setCustomLayerOrder([layer3.id(), layer.id(), layer2.id()])
+        app.processEvents()
+        self.assertEqual([l.id() for l in prj.layerOrder()], [layer3.id(), layer.id(), layer2.id()])
+
+        # no custom layer order
+        bridge.setHasCustomLayerOrder(False)
+        app.processEvents()
+        self.assertEqual([l.id() for l in prj.layerOrder()], [layer.id(), layer2.id(), layer3.id()])
+
+        # mess around with the project layer order
+        prj.setLayerOrder([layer3, layer, layer2])
+        app.processEvents()
+        # make sure bridge respects this new order
+        self.assertTrue(bridge.hasCustomLayerOrder())
+        self.assertEqual(bridge.customLayerOrder(), [layer3.id(), layer.id(), layer2.id()])
+
+        # try reordering through bridge
+        bridge.setHasCustomLayerOrder(False)
+        app.processEvents()
+        self.assertEqual([l.id() for l in prj.layerOrder()], [layer.id(), layer2.id(), layer3.id()])
+        root = prj.layerTreeRoot()
+        layer_node = root.findLayer(layer2.id())
+        cloned_node = layer_node.clone()
+        parent = layer_node.parent()
+        parent.insertChildNode(0, cloned_node)
+        parent.removeChildNode(layer_node)
+        app.processEvents()
+        # make sure project respects this
+        self.assertEqual([l.id() for l in prj.layerOrder()], [layer2.id(), layer.id(), layer3.id()])
+        self.assertFalse(bridge.hasCustomLayerOrder())
+
+if __name__ == '__main__':
+    unittest.main()